Indirect heat exchanger



Dec. 29, 1959 AKE B. LJUNGSTROM 2,919,114

INDIRECT HEAT EXCHANGER Filed Dec. 30, 1957 2 Sheets-Sheet 1 /4/1EB/RGER LJUNGSTR OM INVENTOR.

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1959 I AKE B. LJUNGSTROM 2,919,114

INDIRECT HEAT EXCHANGER 2 Sheets-Sheet 2 Filed Dec. 30, 1957 A KEB/RGE/E L JUNGS re 0 INVENTOR.

ATTORNEY United States atent Ofiice 2,9 l 9,1 14 Patented Dec. 29, 1959INDIRECT HEAT EXCHANGER Ake Birger Ljungstriim, Stockholm, Sweden,assignor to Aktiebolaget Rosenblads Patenter, Stockholm, Sweden, acorporation of Sweden Application December 30, 1957, Serial No. 705,837

Claims priority, application Sweden January 7, 1957 1 Claim. (Cl. 2571)It is previously known in indirect heat exchangers having two separatepassage systems to which two heatexchanging media are supplied from anouter pipe-line system with detachable connections to the heatexchanger, to arrange the heat exchanger in such a manner that, afterdisconnection, it can be turned from a certain connecting position inrelation to this outer pipeline system into a new connecting position inrelation to the pipe-line system, whereby the medium which waspreviously directed through one passage system, in the new connectingposition is passed through the other passage system and vice versa, sothat a so-called passage changing will take place. If one medium is aptto precipitate sediments, for example incrustations in the heatexchanger which may be dissolved by the other medium, the sediments canbe periodically removed by such a passage changing before they have hadtime to collect in too troublesome quantities.

It is also known that if a heat-exchanging medium precipitates sedimensor deposits, for example fibres, sludge, etc., which is apt to becomecaked in the passage system of the heat exchanger the best way to removethese deposits by mechanical flushing is by passing the flushing mediumthrough the passage system in a different direction to that in which thedeposits have become caked. In many cases it is not necessary to haveresort to flushing with any special medium if the depositing medium ispassed periodically in dilferent directions through the passage system.

The main object of the present invention is to provide an arrangementfor carrying out change of passages by turning the heat exchanger sothat any of its passage systems simultaneously with the change ofpassages will be passed by fiuid in a dilferent direction to that whichexisted before the change of passages.

The main characteristic feature of the invention is that there arearranged in fixed connection to the heat exchanger an inlet and anoutlet for one of the passage systems as well as an inlet and an outletfor the other passage system, each of said inlets and outlets, four inall, being connected by four detachable pipe-connections to one of fourpipes associated with an outer, fixed pipe-system, in which two pipesserve to convey one medium and two pipes to convey the other mediumrespectively to and from the heat exchanger, which is mounted to turnaround a revolving axis around which the four detachablepipe-connections are arranged in a circuit in such a way that in thiscircuit every alternate pipe-connection connects one pipe for one mediumto one passage system, while alternate pipe-connection connects a pipefor the second medium to the second passage system through the saidinlets and outlets.

Some embodiments of the invention will now be described with referenceto the accompanying drawings in which Fig. 1 shows a heat-exchanger inlateral section arranged according to the invention,

Fig. 2 shows a top view of the arrangement in Fig. 1,

Figs. 3, 4 and 5 show the same arrangement with the heat exchanger indifierent turning positions as compared with Fig. 1,

Fig. 6 shows a side view of another type of heat exchanger according tothe invention,

Fig. 7 shows the arrangement according to Fig. 6, in section along theline VIIVII in the latter figure,

Fig. 8 shows the arrangement according to Fig. 6 in section along theline VIII-VIII in the latter figure.

Figs. 9 and 10 show the arrangement according to Fig. 6 with the heatexchangers in different turning positions as compared with Fig. 6, and

Fig. 11 shows the heat exchanger according to Fig. 6 arranged in amodified manner according to the invention, and in a differentoscillating position from that in Fig. 6.

Identical details are indicated in the different figures with the samereference characters.

The illustrations are diagrammatic and are only intended to serve asexamples. Thus, two different types of heat exchangers are shown, forexample, although any kind of two-passage type whatsoever can bearranged in conformity with the invention.

1 is a tubular heat exchanger in which pipes 2a and 2b having connectingflanges 4a and 4b respectively communicate with the tubes 6, and thepipes 3a and 3b having connecting flanges 5a and 5b respectivelycommunicate with the chamber 7 surrounding the tubes. The connectingflanges 4a, 4b, 5a and 5b are detachably connected with other flanges10a, 10b, 11a and 11b respectively, associated with outer pipes 12a,12b, 13a, and 13b respectively. The heat exchanger is mounted to turn onpivots 8 in bearings 9 in a frame, and the points of connection betweenthe flanges are arranged in square formation in relation to one anotherin a plane perpendicular to the revolving axis and symmetrically in acircuit round this axis. Two heatexchanging media are conveyed throughthe outer pipes and flanged pipe connections to and from the heatexchanger through this respective pair of flange connections arrangeddiagonally opposite one another in the formation, one medium flowingthrough the two pipes 12a and 12b and the other medium through the twopipes 13a and 13b. It is assumed in the following that the direction offlow is from a to b in each pair of pipes, although item also be in theopposite direction in either or both pairs.

As a result of the symmetrical square grouping of all flanges around thepivot axis of the heat exchanger the latter can be connected to theouter pipes by means of these flanges in four dilferent turningpositions of the heat exchanger, illustrated in Figs. 1, 3, 4 and 5respectively.

In the turning position according to Fig. 1 the heat exchanging mediawill flow along the following courses: Medium 1; from the outer pipeline 12a through pipe line 2a, the tubes 6 downwards and through thepipe line 2b to the outer pipe 12b. Medium 2; from the outer pipe 13athrough the pipe line 3a, the chamber 7 round the tubes and pipe line 3bto the outer pipe line 13b.

In the turning position according to Fig. 3, to the right in relation tothe position according to Fig. 1, the courses will be as follows:

Medium 1; from the outer pipe line 12a through pipe line 311, thechamber 7 round the tubes and through pipe line 3b to the outer pipeline 12b.

Medium 2; from the outer pipe line 13a through pipe line 2b, the tubes 6and the pipe line 2a to the outer pipe line 13b.

' Thus in this position the heat-exchanging media have changed courseswith one another through the heat exchanger compared with the positionaccording to Fig. 1, that is to say a so-called changed of passages hasbeen effected. Moreover, the media pass through the tubes in the reversedirection, that is to say from pipe 2b to pipe 2a instead of in theopposite direction according to Fig. l.

' The same change of passages arises also in the turning positionaccording to Fig. 4, 90 to the left in relation to that in Fig. 1, buthere the medium through the space around the tubes passes in theopposite direction from pipe 3b to pipe 3a instead of in the oppostiedirection according to Fig. 1.

In the turning position according to Fig. 4, finally, 180 in relation tothat in Fig. 1, the pipes 211 and 2b, on one hand, and the pipes 30 and3b, on the other hand, only have'exchanged places. There has been nochange of passages. Both passage systems, on the other hand, are passedby the media in reverse direction, that is to say from pipe 2b to pipe2a and from pipe 3b to pipe 3a respectively instead of in the oppositedirection according to Fig. 1.

Starting from the position according to Fig. 1, the position accordingto Fig. 3 consequently implies a change of passages with reverseddirection of flow in one passage system of the heat exchanger, theposition according to Fig. 4 a change of passages with a reversal fiowin the second passage system of the heat exchanger, and the positionaccording to Fig. 5 a reversed direction of flow in both passage systemswithout any change of passages.

With this arrangement it is therefore possible to run the heat exchangerwith a periodical change of passages in combination with reversed flowin either of the two passage systems of the heat exchanger, or withperiodical reversing of the flow simultaneously in both passagesysterns.

Such an arrangement in heat exchangers of another type is exemplified byFigs. 6, 7 and 8. In principle it is analogous to the arrangement justdescribed, as far as pipe-connections and the turning of the heatexchanger are concerned. The difi'erence is that the heat exchanger 1 isexchanged for a heat exchanger 1a of the crosscurrent type with planeheat transmitting walls 14, which form between them slot-like passages6a and 7a respectively for the heat-exchanging media. The pipes 2a and2b communicate with the passages 6a instead of with the passages 6 ofthe tube in the preceding example, and the pipes 3a and 3b communicatewith the passages 7a instead of with the space 7 round the tubes in thisexample. One medium is conveyed through the heat exchanger from pipe 12ato pipe 12b from above and downwards in the figure as shown by thedash-line arrow, and the second medium from pipe 13a to pipe 13b fromleft to right in the figure as shown by the full-line arrow.

In turningposition of the heat exchanger according to Fig. 6 the mediumflowing in the direction of the dash-line arrow will pass through thepassage 6a, and the medium flowing in the direction of the full-linearrow will pass through the passages 7a.

In the turning position according to Fig. 9, 90 to the right of theposition in Fig. 6 (see character 15) a change of passages is effectedin the same way as in turning of the heat exchanger 1 from the positionin Fig. 1 to the position in Fig. 3, and in addition thereto the passagesystem 6a will be passed by the medium in the reverse direction to thecase before the turning.

The same change of passages is efiected in the turning positionaccording to Fig. 10, 90 to the left from the position in Fig. 6, and inaddition the passages system 7a will be passed by the medium in thereverse direction to that before the turning.

Finally, in the turning position according to Fig. 11, 180 from theposition in Fig. 6 there will be a complete turn round of the directionsin which both passage systems are passed by the media without any changeof passages.

Fig. 11 shows in addition how the connections between the outer pipesand the pipes which move together with the heat exchanger can bearranged in a radial instead of an axial direction as in the otherfigures. In this case the flanges have cylindrical connection surfaceswith a radius equal to the distance to the turning axis of the heatexchanger so that the turning can be carried out without difiiculty, butother arrangements may be imagined, such as detachable spacing pieces,etc. Instead of flanges other types of pipe joints can of course beused.

When, as shown in the figures, the detachable pipe connections arearranged exactly symmetrically in square formation round the turningaxis of the heat exchanger in one and the same plane at right angles tothis axis, the parts of the heat-exchanger connections in each of theturning positions spaced at an angle of will occupy exactly exchangedpositions. The outer pipe-lines can consequently be rigid and yetadapted to be connected in every such turning position.

If these pipe-lines are flexible, or in the extreme case consist of ahose or include a hose section, the requirement of an exact exchange ofpositions between the parts of connections of the heat-exchanger can,however, be more or less mitigated, that is to say large or smalldeviations may be made from the square formation, symmetry or the mutualplane individually or jointly without abandoning the possibility ofconnection in the different turning positions. The essential thing isthat the detachable joints are arranged in their circuit around theturning axis in such a way that every second connection (in the squareformation the diagonally opposite connections) connects an outer pipefor one medium to one of the passage systems of the heat exchanger andevery second connection connects such a pipe for the other medium to theother passage system of the heat exchanger.

What I claim is:

Arrangement in indirect heat exchangers comprising in combination twoseparate passage systems for two heat exchanging media, a first inletand a first outlet for one of said passage systems firmly connected tothe heat exchanger and at opposite sides thereof, a second inlet and asecond outlet for the other passage system firmly connected to the heatexchanger and at oppositely sides thereof, four detachable pipeconnections for connecting the individual inlets and outlets, four inall, to one each of four pipes associated to an outer, fixed pipesystem, two pipe lines of which are arranged to convey one medium andthe other two pipe lines of which are arranged to convey the othermedium to and, respectively, from the heat exchanger, said detachablepipe connections, facing in approximately one and the same Plane, beingarranged in square formation as viewed against that plane and supportingmeans arranged to permit turning of the heat exchanger supported by saidmeans around a revolving axis perpendicular to said plane.

References Cited in the file of this patent UNITED STATES PATENTS2,508,119 Lockman May 16, 1950

